Electro-mechanical oscillators are used to drive electro-optical mechanisms such as printers, scanners, barcode readers and similar devices. A torsion oscillator, which is one type of oscillation device, typically includes a mirror that is disposed on a plate that is cut or etched from a silicon wafer and supported on trunnions. In one embodiment, magnets are attached to the plate and when electric current passes through a nearby coil, a force is exerted on the magnets which is translated to the plate. This force causes oscillation of the plate which twists the trunnions. Other forces may be employed to make such a system oscillate, such as electric fields or mechanical forces. The plate is excited to oscillate, preferably at or near a resonant frequency, by an oscillation controller that causes alternating current to pass through the coil at or near the resonate frequency or at or near a harmonic of the resonant frequency. The angle of the mirror moves sinusoidally with respect to time at a certain amount of sweep (termed amplitude), at a certain repetition rate (termed frequency), and with a potential lack of symmetry (termed median offset). Unfortunately, the characteristics of mirrors can vary significantly due to physical variations from manufacturing tolerances, and changing environmental conditions, particularly temperature changes, that typically affect the resonant frequency. Consequently, the amplitude, frequency and median offset of an oscillator must be stabilized for useful operation. What is needed is an effective method for controlling scan time intervals in these systems.